Databases · Senior · Question 52 of 75

What is the role of `shared_buffers` and the OS page cache in PostgreSQL performance?

✓Correct answer: PostgreSQL caches pages in its shared buffers and also relies on the OS cache; a working set that fits in memory avoids disk reads
2The OS cache isn't used by PostgreSQL
3shared_buffers stores query results for reuse

Explanation

A common starting point is about 25% of RAM for shared_buffers. EXPLAIN (BUFFERS) shows hits versus reads.

Further reading

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